Eustache auguste cresson



(No Model.)

B. A. CRBSSON. COMBINED PERPETUAL CALENDAR AND WATCH TRINKET 0R CHARM.

Patented May 19,1891.

FIEl.

UNITED STATES PATIENT OFFICE.

EUSTACHE AUGUSTE CRESSON, OF PARIS, FRANCE.

COMBINED PERPETUAL CALENDAR AND WATCH TRlNKET OR CHARM.

SPECIFICATION forming part of Letters Patent No. 452,450, dated May 19, 1891. Application filed March 4, 1891. Serial No. 383,700. (No model.) Patented in France August 23, 1889, No. 200,364.

To all whom it may concern:

Be it known that I, EUSTAOHE AUGUSTE CRESSON, of the city of Paris, France, have invented a Perpetual Calendar and Watch Trinket r Charm, (for which I have obtained Letters Patent in France for fifteen years, dated August 23, 1880, No. 200,364,) of which the following is a full, clear, and exact description.

My invention relates to a perpetual calendar especially suitable for attachment to a watch-chain in the manner of a coin, medal,

or charm. The calendar consists, essentially,

of a ring within which a disk is fitted to revolve, the ring and disk being divided into segments inscribed for reference the one to the other, in the manner hereinafter described, for the purposes for which such a calendar is required.

In the accompanying drawings, forming part of this specification,Figure 1 represents the side of the calendar bearing upon the rotating disk the names of fliG'lIlOlllIllS, and Fig. 2 the opposite face bearing the days of the month, the inscriptions on both faces being contained in seven sector-shaped divisions arranged in a certain order. The outer ring bears upon both faces the days of the week inscribed in segments corresponding in length and number to the divisions of the disk. Fig. 3 represents the peripheral rim of the outer ring developed in the flat, bearing, in seven segments or divisions corresponding to those of the faces, numbers by which to find the key to the instrument, which is the first day of the year. Fig. at shows the calendar a watch-trinket.

The day of the week on which the first day of the year falls being known, in order to find the day of the week corresponding to any given date of any month the name of the said month is placed opposite the day of the week on which the first day of the year falls, and then by referring to the opposite face of the disk the date of the month will be found below the name of the day sought for.

First example-To find on which day of the week the 21st of March, 1891, will fall, the first day of the year 1891 being known to be Thursday, the month of March is to be placed opposite to Thursday by rotating the disk, when it will be found on referring to the opposite face of the calendar that the number 21 is opposite to Saturday, thus showing that the 21st of March, 1891,.will be Saturday.

Second example-To find the date of the second Saturday in October, 1891, place OctoberoppositetoThursday,January 1,1891, and then find on the opposite face of the calendar the second date beneath the Saturday, which is 10. Consequently the second Saturday in October, 1891, is on the 10th day of the month.

To find the day of the week on which the first day of any year falls, which, as above mentioned, forms the key to the use of the instrument, the one of the three numbers 20 48 76 (inscribed upon the month-disk) which most nearly corresponds to the number of the year in the century is to be subtracted therefrom, and by referring to the number on the rim corresponding to the remainder the first day of the year will be found beneath it, which is the key sought for; or the year may be divided bythe constant number 28, which gives the same result.

Ercmtple for 189l.91 76 15, is found on the rim above Thursday on the face, thus showing that the first day of the year was a Thursday. The key may thus be found for any year in a similar manner. If in subtractingin the above manner the remainder is repeated on the rim. this will indicate leapyear, in which case the following method is adopted: For the monthsof January and February thekey will be the day found upon the rim below the first number to the right. From the month of March it will be the day found below the second figure to the left. For example, the year 1892 is found to be leap year, as by subtracting from 92 the number most nearly approaching it, which is 76, there remains 16, which is found repeated twice upon the rim. Below the 16 on the right is found Friday, which serves as the key for the months of January and February, and below the 16 to the left is found Saturday, which forms the key from March to the end of the year.

I claim 1 1. A perpetual calendar consisting of an inner disk revoluble within an encircling rim and bearing on the one side the months of the your and on the other the days oi. the I thereon for ii'iterreference, as described, the month in combination with the days, of the f calendar being mounted as a watch trinket; week upon the faces of the ring'and numbers or charm, as set forth. inscribed upon the peripheral rim by which 'lhe foregoingspecification of my perpetual 5 the key to the use of the instrument is found, i calendar signed by me this 10th day of Feb- I5 as hereinbefore described, and illustrated in ruury, 1891.

the drawings. EUSTACH E AUGUSTE (/RESSON.

2. The hereiu-deseribcd perpetual calendar, \Vitnesses: consisting of a disk fitted t0 revolve Withinai R0131. M. HOOPER,

10 ring, both havingnmnes and figures inscribed l ALBERT MOREAU. 

